Cellulose anthranilate textile fibers and process for making the same



States Patent ice CELLULOSE ANTHRANILATE TEXTILE FIBERS AND PROCESS FOR MAKING THE SANIE Wilson A. Reeves and Ricardo H. Wade, Metairie, La.,

assignors to the United States of America as represented by the Secretary of Agriculture No Drawing. Application July 24, 1958 Serial No. 750,837

7 Claims. (Cl. 8116.2)

(Granted under Title 35, US. Code (1952), sec. 266) A non-exclusive, irrevocable, royalty-free license in the invention herein described, throughout theworld for all purposes of the United States Government, with the power to grant sublicenses for such purposes, is hereby granted to the Government of the United States of America.

This invention relates to the production and use of cellulosic textile fibers containing anthranilate radicals [-OC(O)C H NH attached to oxygen atoms of the cellulose molecules of the fibers.

Among the textile fibers (i.e., fibers which have been woven, or are capable of being woven) the native or natural vegetable textile fibers are unique. Chemically they are substantially the same as various man-made textile fibers. They are composed of cellulose in the form of high polymers in which anhydroglucose units are the recurring structural units. However, the natural vegetable textile fibers have a unique combination of many desirable textile properties, due to the complex laminated structures in which their cellulose molecules are arranged. For example, in the American Dyestufl Reporter, February 15, 1954, pages 2 to 10, it is pointed out that the natural textile fibers, such as cotton fibers, possess a combination of over fifty properties to which their outstanding performance under all types of service conditions are due. The article also points out that, when the proper conditions for reaction are found, native vegetable fibers can be chemically modified so that they acquire certain new fiber properties while retaining the intrinsic structure that gives them a combination of desirable textile properties.

It has been reported previously that anthranilate esters can be made by reacting isatoic anhydride with primary alcohols containing from one to five carbon atoms by carrying out the reaction at about 50 C. in an inert solvent or in an excess of the alcohol. A very low degree of esterification can be obtained when a polyalcohol is reacted with isatoic anhydride in a water solution. Isatoic anhydride dissolves in water to the extent of 0.03% at 25 C. and 0.25% at 65 C.

The primary object of this invention is to provide a process of chemically modifying textile fibers composed of cellulosic molecules arranged in the complex laminated structure characteristic of natural vegetable textile fibers, to produce textile fibers that have substantially the same molecular arrangement and textile properties, but have difierent chemical properties. A further object is to provide a process of esterifying cellulose hydroxy groups while they are attached to cellulose molecules that are arranged in the complex laminated structure characteristic of natural vegetable textile fibers, so that the hydrogen atoms of such hydroxy groups are replaced by anthranilate [-OC(O)C H NH A further object is to provide a process of esterifying cellulosic textile fibers that approaches the simplicity and ease of operation found in the conventional additive finishing processes. etherified cellulosic textile fibers, composed of cellulose A further object is to provide novel molecules and esterified cellulose molecules arranged in the complex laminated structure characteristic of natural vegetable textile fibers, in which fibers are the radicals that replace hydrogen atoms of cellulose hydroxy groups consist essentially of anthranilate radicals.

In general, in accordance with the present invention, cellulosic textile fibers composed of cellulosic molecules arranged in the complex laminated structure characteristic of natural vegetable textile fibers, are produced by: wetting cellulosic textile fibers composed of hydroxyl group-containing cellulosic molecules arranged in the complex, laminated structure characteristic of natural vegetable textile fibers with water miscible organic liquids such as dimethyl sulfoxide, dimethyl formamide, acetic acid, and acetone which are unreactive toward cellulose, containing from about 0.1 to 12 weight percent of a dissolved strong base and from about 1.0 to about weight percent of dissolved isatoic anhydride,

- and heating the .so-treated fibers at a temperature above group per 30 anhydroglucose units to 1 anthranilate group per 2 anhydroglucose units.

In general, the esterified cellulosic textile fibers produced in accordance with this invention retain substantially all of the textile properties that characterize the natural vegetable textile fibers, and are useful wherever a natural vegetable textile fiber is useful. For example, a cotton cloth anthranilated to a nitrogen content of 3.1 percent (corresponding to about 1 anthranilate radical per 2 anhydroglucose units) is almost indistinguishable from the untreated cloth, on the basis of hand, feel, and appearance, and can be used wherever the untreated cloth is used. However, such an esterified cotton cloth, and all of the estertified cellulosic textile fibers produced in accordance with this invention, ex

Substantially any cellulosic textile fibers composed of cellulosic molecules containing cellulose hydroxy groups arranged in the complex laminated structure characteristic of the natural vegetable textile fibers, can be esterified to produce esterified cellulosic textile fibers 'in accordance with this invention. In addition, substantially any cellulosic fibers containing cellulose hydroxy groups can be etherified by the simple process provided by this invention.

The fibers can be treated in the form of free fibers, sliver, yarn, thread or fabric. The apparatus and handling techniques usually employed for the chemical treatment of textile fibers can be used. In general, the employment of the fibers in the form of spun textiles such as threads or cloth is preferred.

Illustrative examples of fibers which can be employed include cotton, fiax, ramie, and the like natural vegetable textile fibers; mercerized, partially acetylated, partially cyanoethylated, or the like chemically modified natural vegetable textile fibers that contain at least one cellulosic OH group per anhydroglucose unit and the intrinsic elements of the structure of natural vegetable textile fibers; and, derived or regenerated cellulosic textile fibers, such as the fibers regenerated from the natural Patented Feb. 23, 1960.

vegetable textile fibers by the cuprammonium or the viscose process. The natural vegetable textile fibers are particularly suitable fibers for employment in the present process.

Substantially any inert solvent, which is substantially unreactive toward cellulose and is appreciably miscible with isatoic anhydride and the strong base used as a catalyst, can be used as the reactant-containing liquid, i.e., the liquid which contains the isatoic anhydride and the 'basic catalyst. Illustrative examples of suitable liquids include dimethylformamide; dimethylsulfoxide; dimethylformamide or dimethylsulfoxide containing a minor amount of water, acetic acid, acetone, or other ketones. Dimethylsulfoxide is a preferred liquid for employment in the present process. Isatoic anhydride will dissolve to the extent of about 55 grams in 100 grams of dimethylsulfoxide at 65 C.

Substantially any strong base capable of dissolving along with isatoic anhydride in an effective concentration, in the reactant-containing liquid, can be used as the catalyst. Illustrative examples of suitable strong bases include: the quaternary ammonium hydroxides such as benzyl trimethyl ammonium hydroxide, dibenzyl dimethyl ammonium hydroxide, and the like; the alkali metal hydroxides; sodium acetate, potassium acetate, and the like strong bases. The use of potassium acetate is preferred.

In addition to the isatoic anhydride and the basic catalyst, the reactant-containing liquid can contain textile fiber treating agents; such as softening agents, lubricating agents, flammability retarding agents, and the like, which are unreactive toward the isatoic anhydride and the basic catalyst.

At the time the fibers are Wetted with the reactantcontaining liquid, the reactant-containing liquid can be maintained at substantially any temperature above its freezing point and below its boiling point; but, in general, the reactant-containing liquid is preferably maintained at about room temperature (i.e. from about 20 to 65 C.). The step of wetting the fibers with the reactant-containing liquid can be done by any convenient method. A conventional textile padder is most satisfactory.

The proportionate amount of catalyst contained by the reactant-containing liquid can be varied widely. Both the catalyst and the isatoic anhydride can be incorporated in the reactant-containing liquid in the form of solutions, emulsions or dispersions of compounds in a liquid in which they are appreciably soluble. The proportion of the catalyst is not critical, but the use of a proportion materially smaller than about 0.1% of the weight of the reactant-containing liquid tends to result in an undesirably slow reaction at the moderate or lower reaction temperatures; and the use of a proportion of about 12% causes a reduction in rate of reaction. From about one to about six percent of the catalyst is preferred.

In general, the proportion of isatoic anhydride in the reactant-containing liquid should be such that the amount of liquid left in contact with the fibers after padding, preferably from about 70 to 110 parts of liquid per 100 parts of fibers, contains about twice the amount of isatoic anhydride for the amount of cellulose OH groups it is desired to convert to anthranilate ester groups. The use of an isatoic anhydride concentration of as little as 1% by weight of the reactant-containing liquid imparts an appreciable change to cotton textile fibers. In the case of cotton fibers (where about 70 to 110% of liquid is left in contact with the fibers after the mechanical removal of excess liquid) an isatoic anhydride content of 25% by weight of the reactantcontaining liquid provides an adequate molar excess of isatoic anhydride for the conversion of about 1 cellulose OH group per 4 anhydroglucose units of the fibers.

The fibers can be reacted with the isatoic anhydride contained in the amount of reactant-containing liquid retained in the porous portions of the fibers at substan-- tially any temperatures above about 50 C. and below about 170 C. However, in order to use up the isatoic anhydride in a reasonable time, the reaction is preferably conducted at a temperature of from about to 150 C. In general, reaction times of from about 2 to 15 minutes, with the longer times being used with the lower temperatures, are sufficient to convert the isatoic anhydride to O-linked anthranilate radicals. Where a high degree of etherification is desired, the fibers can be subjected to a plurality of controlled impregnations and heatings with the heatings conducted so that the fibers are partially or substantially completely dried between each controlled impregnation.

The esterified cotton yarn and cloth produced in accordance with this invention exhibit many useful and novel properties. The anthranilated cotton fibers dye easily with methylene blue dye (a basic dye) and also dye readily with Kiton fast red 3 GLL (an acid dye). The fibers are dyed with Celliton fast yellow RRA (an acetate dye) and with Chlorantine fast blue 4 GL (a direct cotton dye). In a mixture of the Celliton fast yellow and pontamine fast blue RRL the fibers are dyed yellowish green. The free amino groups undergo reactions characteristic of aromatic amines.

The following examples are illustrative of the details of at least one method of practicing the invention.

EXAMPLE 1 Cotton fabric (48 x 48 sheeting) was padded through a solution consisting of 0.37 part of sodium hydroxide, 11 parts of Water, 14.7 parts of isatoic anhydride, and 74 parts of dimethylsulfoxide. The sodium hydroxide was first dissolved in the water and then the alkali solution was added to the dimethylsulfoxide before dissolving the isatoic anhydride. The wet fabric which contained about 100% wet pickup of the solution was divided into three pieces A, B, and C, and then treated as follows: A was heated in an electrically heated forced draft oven for 30 minutes at 50 C.; B was heated 3 minutes at 130 C.; and C was heated 6 minutes at 130 C. All the fabrics were then Washed in hot (about -130 C.) running water for 2 hours and then allowed to dry and equilibrate for about 16 hours. Fabrics B and C had a weight gain of anthranilate ester groups of 9%; sample A had a weight gain of slightly less than 9%. The hand and feel of the treated fabric was essentially the same as that of untreated fabric. The treated fabrics dyed readily with Kiton fast red 3 GLL.

EXAMPLE 2 Seven pieces of cotton fabric were padded in solutions containing isatoic anhydride and then heated to promote esterification. The details of the treating solutions and the heating conditions are described in Table I. After heating the fabrics, they were washed about two hours in hot water and then air dried. The extent of the reactions is also shown in Table I. The extent or degree substitution indicated by the weight pickup in sample 4 is about 1 anthranilate group per two anhydroglucose units. From the table it can be seen that dimethylsulfoxide is a much better solvent than dimethylformamide for carrying out the reaction. It can also be seen that about 45% catalyst is much better than no catalyst or 12.9% catalyst.

Fabric about equivalent to sample 3 (containing a 20% weight gain) was placed in a moist humus soil bed along with an untreated control sample of fabric. After one week the control fabric had completely deteriorated. The isatoic anhydride treated fabric remained essentially unattacked by micro-organisms after about 4 months.

Samples of the anthranilated fabrics were diazotized and coupled with a number of phenolic compounds to produce highly colored fabrics.

"nth-J Table l Reaction Extent of Composition of Treating Solution Conditions Reaction With the Cellulose salrInple Isatoic Dimethyl- Dimethyl- Catalyst and Temper- Time, Weight Nitrogen anhysulfoxide, formamide, Water, concentration, ature, mingain, introdrlde, percent percent percent percent O. utes percent duced, percent percent 15 71 9.3 f qff j 140 4 4 15 71 9 a f? 140 4 7.3 26.5 60 9.0 QP ffR- 140 4 10.5 1 68 26 so 9 {f q ff?j 140 4 31.5 27.7 63.8 8.5 none 140 4 3.6 0.60 26.6 61.2 8.2 {ff ff j 160 4 1.51 14 64.3 as f? 140 4 2.8

1 Sample 4 represents a retreatment of sample 3. Nitrogen analyses were not made on these samples.

EXAMPLE 3 Cotton sheeting was padded in a solution containing 2.7% potassium acetate, 8.3% isatoic anhydride, 45% dimethylsulfoxide, and 45 glacial acetic acid. The wet fabric was heated for 4 minutes at 140 C. and then washed thoroughly in hot water. The weight gain was 4.8% and the fabric contained 0.59% nitrogen.

We claim:

1. A process for anthranilating cellulosic textile fibers containing at least 1 free hydroxyl group per anhydroglucose unit which comprises reacting said fibers with an aqueous solution comprising 1 to 30% of isatoic anhydride, 1 to about 12% of a strong base from the group consisting of an alkali metal hydroxide, a quaternary ammonium hydroxide, and an alkali metal acetate, and a water miscible organic solvent for isatoic anhydride which is inert to cellulose until there is introduced into the cellulose molecules about 1 anthranilate group per 30 anhydroglucose units.

2. A process for producing anthranilated cellulosic textile fibers the cellulose molecules of which are arranged in the complex laminated structure characteristic of natural vegetable textile fibers, said fibers containing at least one free hydroxyl group per anhydroglucose unit, which comprises wetting the cellulosic textile fibers with an aqueous solution containing a water miscible organic solvent for isatoic anhydride which is inert to cellulose,

about from 1 to 12 weight percent of a dissolved strong base from the group consisting of an alkali metal hydroxide, a quaternary ammonium hydroxide, and alkali metal acetate and from about 1 to 30 weight percent dissolved isatoic anhydride by passing the textile fibers through the solution, removing excess solution from the textile fibers, and then heating the fibers at a temperature of about from to C. for about from 2 to 30 minutes until there is introduced into the cellulose molecules from about 1 anthranilate group per thirty anhydroglucose units to l anthranilate group per 2 anhydroglucose units.

3. The process of claim 2 wherein the strong base is an alkali metal hydroxide.

4. The process of claim 2 wherein the strong base is a quaternary ammonium hydroxide.

5. The process of claim 2 wherein the strong base is an alkali metal acetate.

6. The process of claim 2 wherein the water miscible organic liquid is dimethylformamide.

2,150,968 Gunther Mar. 21, 1939 Gunther Dec. 29, 1925 

2. A PROCESS FOR PRODUCING ANTHRANILATED CELLULOSIC TEXTILE FIBERS THE CELLULOSE MOLECULES OF WHICH ARE ARRANGED IN THE COMPLEX LAMINATED STRUCTURE CHARACTERISTIC OF NATURAL VEGETABLE TEXTILE FIBERS, SAID FIBERS CONTAINING AT LEAST ONE FREE HYDROXYL GROUP PER ANHYDROGLUCOSE UNIT, WHICH COMPRISES WETTING THE CELLULOSIC TEXTILE FIBERS WITH AN AQUEOUS SOLUTION CONTAINING A WATER MISCIBLE ORGANIC SOLVENT FOR ISATOIC ANHYDRIDE WHICH ILS INERT TO CELLULOSE, ABOUT FROM 1 TO 12 WEIGHT PERCENT OF A DISSOLVED STRONG BASE FROM THE GROUP CONSISTING OF AN ALKALI METAL HYDROXIDE, A QUATERNARY AMMONIUM HYDROXIDE, AND ALKALI METAL ACETATE AND FROM ABOUT 1 TO 30 WEILGHT PERCENT DISSOLVED ISATOIC ANHYDRIDE BY PASSING THE TEXTILE FIBERS THROUGH THE SOLUTION, REMOVING EXCESS SOLUTION FROM THE TEXTILE FIBERS, AND THEN HEATING THE FIBERS AT A TEMPERATURE OF ABOUT FROM 50 TO 170* C. FOR ABOUT FROM 2 TO 30 MINUTES UNTIL THERE IS INTRODUCED INTO THE CELLULOSE MOLECULES FROM ABOUT 1 ANTHRANILATE GROUP PER THIRTY ANHYDROGLUCOSE UNITS TO 1 ANTHRANILATE GROUP PER 2 ANHYDROGLUCOSE UNITS. 